Hydrogen is used widely in various fields, including chemistry, chemicals, electricity, metal, and glass industry. Since hydrogen produces only water as waste, attention has recently been paid to hydrogen as a clean energy which replaces fossil fuel. For example, research and development are being made for the application of hydrogen to hydrogen-fuel cells, hydrogen-fueled vehicles, etc. Thus, a large amount of hydrogen will be utilized in the future. As conventional hydrogen producing methods there are known, for example, a method of producing hydrogen by electrolyzing water (electrolyte) and a method of producing hydrogen by modifying a hydrocarbon fuel gas such as natural gas (see, for example, Patent Document 1).
Patent Document 1:    Japanese Patent Laid-Open Publication No. 2004-115326